- Ethylammonium nitrate (EAN)/Tf2O and EAN/TFAA: Ionic liquid based systems for aromatic nitration
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Acting as in situ sources of triflyl nitrate (TfONO2) and trifluoroacetyl nitrate (CF3COONO2), the EAN/Tf 2O and EAN/TFAA systems, generated via metathesis in the readily available ethylammonium nitrate (EAN) ionic liquid as solvent, are powerful electrophilic nitrating reagents for a wide variety of aromatic and heteroaromatic compounds. Comparative nitration experiments indicate that EAN/Tf2O is superior to EAN/TFAA for nitration of strongly deactivated systems. Both systems exhibit low substrate selectivity (K T/KB = 5-10) in (Figure presented) between values reported for covalent nitrates and preformed nitronium salts.
- Aridoss, Gopalakrishnan,Laali, Kenneth K.
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experimental part
p. 8088 - 8094
(2011/11/13)
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- NITRO DERIVATIVES OF THE THIOPHENE SERIES. 4. NITRATION OF THIOPHENE DERIVATIVES WITH METAL NITRATES IN ACETIC ANHYDRIDE
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The nitration of 2-formylthiophene, 2-acetothienone, and unsaturated ketones of the thiophene series with copper and aluminum nitrates in acetic anhydride at various temperatures was studied.At low temperatures 2-acetothienone gives a mixture of 4- and 5-nitro isomers, while 2-formylthiphene gives only a 5-nitro-substituted compound in the diacetate form; α,β-unsaturated ketones are not nitrated under these conditions.When the reaction is carried out at 70-90 degC, one can obtain mixtures of nitro ketones in the case of unsaturated ketones; 2-formylthiophene is oxidized to thiophene-2-carboxylic acid, while 2-acetothienone gives a substance, the structure of which could not be established.The reaction of copper and aluminum nitrates with acetic anhydride was investigated by means of thermal and X-ray diffraction analysis.It is shown that the reaction is accompanied by the formation of free nitric acid, and the nitrating agent in these mixtures is consequently the nitronium cation.
- Churkin, Yu. D.,Panfilova, L. V.,Lugovoi, V. D.,Boiko, N. V.
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p. 673 - 675
(2007/10/02)
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